FIG. 1 depicts a portion of conventional head 1 including a conventional perpendicular magnetic recording (PMR) transducer 10 and conventional read transducer 40 separated by an insulator 6, as viewed from the air-bearing surface (ABS). Also depicted is the substrate 2, which may be part of a body of a slider (not separately depicted in FIG. 1). The conventional read transducer 40 includes shields 42 and 48, read sensor 46, and insulator 44. The conventional PMR transducer 10 includes a conventional first pole 12, alumina insulating layer 14, seed layer 16, conventional PMR pole 18, insulating layer 20, write gap 26, top shield 28, and insulating layer 30. Note that the top shield 28 may also act as pole during writing using the conventional PMR transducer 10. The conventional PMR pole 18 and the top shield 80 are surrounded by insulating layers 20 and 30, respectively. The conventional PMR pole 18 has sidewalls 22 and 24.
In conventional applications, the height of the conventional PMR pole 18 is typically less than approximately three-tenths micrometer. The conventional PMR pole 18 also has a negative angle such that the top of the conventional PMR pole 18 is wider than the bottom of the conventional PMR pole 18. Stated differently, the angle θ of the sidewalls is less than 90 degrees in the conventional PMR pole 18 of FIG. 1. A pole having this height and shape is desirable for use in PMR applications.
FIG. 2 depicts a conventional method 50 for forming the conventional PMR transducer 10. For simplicity, some steps are omitted. The seed layer 16 for the conventional PMR pole 18 is deposited and the pattern for the conventional PMR pole 18 formed, via steps 52 and 54, respectively. The material for the conventional PMR pole 18 is plated, via step 56. The remaining seed layer around the conventional PMR pole 18 is removed, via step 58. The conventional PMR pole 18 is then trimmed, via step 60. Consequently, the width of the conventional PMR pole 18 and the negative angle are set in step 60. The insulator 20 is deposited around the conventional PMR pole 18, via step 62. A chemical mechanical planarization (CMP) is performed to planarize the surface and expose the conventional PMR pole 18, via step 64. The surface is planarized in order to allow subsequent processing to be performed as desired. The write gap 26 is provided, via step 66. The top shield 28 is deposited and patterned in step 68. Finally, the region around the top shield 28 is insulated, via step 70.
Although the conventional method 50 can be used to form a conventional PMR transducer 10, vertical variations in the CMU process used in exposing the conventional PMR pole 18 in step 64 are relatively large. In particular, the three-sigma variation in the CMP is on the order of three-tenths micrometer. The variation in the CMP process is thus on the order of the height of the conventional PMR pole 18. As a result, the height of the conventional PMR pole 18 may be difficult to control and fabrication of suitable conventional PMR transducers 10 difficult to repeat. Manufacturing of conventional PMR transducers 10 and, therefore, manufacturing of conventional heads 1 may have a low yield.
Accordingly, what is needed is an improved and more repeatable method for fabricating a PMR pole.